Low-toxicity anti-torsion medium-voltage power cable based on polymer hydrogel material

Abstract

The utility model discloses a low-toxicity anti-torsion medium-voltage power cable based on a polymer hydrogel material. The low-toxicity anti-torsion medium-voltage power cable is structurally characterized in that a cable core is sequentially wrapped by a second wrapping layer, a third wrapping layer, a hydrogel anti-torsion layer, a flame-retardant layer, a fourth wrapping layer and an outer sheath from inside to outside; the cable core is formed by twisting a plurality of flexible wire cores and fillers; the filling is flame-retardant polyurethane foam filling; the second wrapping layer is formed by overlapping and wrapping a layer of double-sided insulating water-blocking tape; the third wrapping layer is formed by overlapping and wrapping a layer of environment-friendly glass fiber flame-retardant tape; the hydrogel anti-torsion layer is formed by extruding organic hydrogel; the flame-retardant layer is formed by extruding a polyurethane material; the fourth wrapping layer is formed by overlapping and wrapping a layer of flame-retardant heat-insulating aramid fiber belt; the outer sheath is formed by extruding a flame-retardant sheath material; each flexible wire core structurally comprises a conductor, a conductor shielding layer, an insulating layer, an insulating shielding layer and a first wrapping layer from inside to outside in sequence. The conductor is a six-type flexible conductor with a circular structure.

Description

Technical Field

[0001] The utility model relates to a low-toxic torsion-resistant medium-voltage power cable based on a polymer hydrogel material, which is suitable for plastic power cables with rated voltages of 3.6 / 6kV to 26 / 35kV and belongs to the technical field of cables. Background Art

[0002] With the continuous development of materials science, how to apply new materials to cables in special usage scenarios while meeting electrical performance requirements and ensuring that the cables' electrical performance, environmental performance, mechanical performance, safety performance, etc. meet the requirements are technical difficulties that need to be solved at present.

[0003] Taking environmentally friendly applications as an example, although power cables have environmental protection requirements such as ROHS2.0, industry users are still not familiar with environmental performance and lack relevant production and testing experience. From the perspective of cable selection and design, it is necessary to provide cable electrical performance on the basis of meeting the environmental protection assessment requirements and improve the flame retardancy and environmental protection and thermal stability of the cable filling and sheath.

[0004] Hydrogel materials in polymer materials are used in waterproof / moisture-proof structures of cables due to their excellent absorption properties, such as:

[0005] The "water-blocking cable" with announcement number CN214203278U includes: two conductors, a first insulating layer, a water-blocking tape, and a sheath; the first insulating layer surrounds the conductors, the conductors are twisted, the water-blocking tape longitudinally surrounds the conductors and the first insulating layer, and partially contacts the first insulating layer, and the sheath surrounds the water-blocking tape; the water-blocking tape includes non-woven fabric and hydrogel, and the water entering the water-blocking cable is absorbed by the hydrogel. The hydrogel content in the water-blocking tape of the cable is limited, and it is wrapped by non-woven fabric fibers. The actual expansion degree when exposed to water is limited, the water-blocking effect cannot be guaranteed, and a large amount of water molecules accumulate in the water-blocking tape, which is easy to cause conductor oxidation.

[0006] The "a moisture-proof power grid distribution cable" with announcement number CN219997923U includes a first elastic rubber sleeve, a second elastic rubber sleeve and an inner protective rubber sleeve. An insulating rubber column is installed at the center of the inner protective rubber sleeve, and the cable conductive core is evenly installed inside the inner protective rubber sleeve. A waterproof inner rubber sleeve is installed on the outside of the inner protective rubber sleeve, and a second elastic rubber sleeve is installed on the outside of the waterproof inner rubber sleeve, and a first elastic rubber sleeve is installed on the outside of the second elastic rubber sleeve. A waterproof outer layer, a hydrogel block and a waterproof inner rubber sleeve are also installed. When the waterproof outer layer is damaged and liquid enters the second elastic rubber sleeve, the hydrogel block can absorb water and swell, and can be filled in the second elastic rubber sleeve and the waterproof inner rubber sleeve to prevent the liquid from continuing to penetrate. The waterproof outer layer, hydrogel block and waterproof inner rubber sleeve of the cable are dispersed in structure, and water molecules are easy to flow along the longitudinal direction of the cable, causing the insulating water tree phenomenon.

[0007] The above two cables only consider using the water absorption characteristics of the hydrogel material to improve the waterproof / water blocking performance of the cable, and the water blocking structure has insufficient performance. The performance of the cable is single, and it has not yet considered improving the fire resistance and other performance of the cable. Utility Model Content

[0008] Technical issues to be solved

[0009] Cables need to meet the requirements of torsion resistance and environmental friendliness in a variety of usage environments, while improving performance in torsion resistance, waterproofness, flame retardancy, etc.

[0010] In the existing technology: hydrogel, a better water-absorbing material, can be used in the water-blocking functional structure of the cable; polyurethane, a better material, can also be used in the water-blocking, flame-retardant and other functional structures of the cable due to its better flame-retardant, water-blocking and corrosion-resistant properties. The use of these two polymer materials has a negative impact on the torsion resistance of medium-voltage power cables.

[0011] Therefore, in the structural design of torsion-resistant medium-voltage power cables, the following aspects are mainly designed:

[0012] 1. Explore the polyurethane flame retardant functional structure of the cable to make it have a positive effect in improving the anti-torsion performance of the cable;

[0013] 2. Explore the hydrogel water-blocking functional structure of the cable, so that it can have a positive effect on improving the cable's anti-torsion performance.

[0014] 3. Explore other functional structures of the cable and make them match the above functional structures, so that the cable has the performance characteristics of water blocking and flame retardancy while realizing its basic functions.

[0015] Technical solutions adopted to solve the above technical problems

[0016] A low-toxic, torsion-resistant medium-voltage power cable based on polymer hydrogel material, the structure of which is:

[0017] It is composed of a second wrapping layer, a third wrapping layer, a hydrogel anti-torsion layer, a flame retardant layer, a fourth wrapping layer and an outer sheath wrapped around the cable core from the inside to the outside in sequence;

[0018] The cable core is composed of a plurality of flexible wire cores and fillers twisted together, and the cable pitch-diameter ratio ranges from 5 to 18 times; the filler is flame-retardant polyurethane foam filler;

[0019] The second wrapping layer is composed of a layer of double-sided insulating water-blocking tape wrapped in an overlapping manner, with an overlap rate of not less than 45%;

[0020] The third wrapping layer is composed of a layer of environmentally friendly glass fiber flame retardant tape wrapped in an overlapping manner, with an average overlap rate of not less than 25% and a minimum overlap rate of not less than 15%;

[0021] The hydrogel anti-torsion layer is formed by extruding an organic hydrogel, and the thickness of the hydrogel anti-torsion layer is 1.60 to 2.50 mm;

[0022] The flame retardant layer is formed by extrusion of polyurethane material, the nominal thickness of the flame retardant layer is 2.50mm to 3.50mm, and the thickness at the thinnest point is not less than 85% of the nominal value;

[0023] The fourth wrapping layer is composed of a layer of flame-retardant heat-insulating aramid tape wrapped in an overlapping manner, with an average overlap rate of not less than 30% and a minimum overlap rate of not less than 20%;

[0024] The outer sheath is made of flame retardant sheath material extruded, with a nominal thickness of not less than 2.50 mm and a thickness at the thinnest point of not less than 90% of the nominal value;

[0025] The structure of a single flexible wire core is: from the inside to the outside, it is the conductor, the conductor shielding layer, the insulation layer, the insulation shielding layer and the first wrapping layer;

[0026] The conductor is a Class VI soft conductor with a circular structure, and the diameter of the metal monofilament constituting the conductor is not greater than 0.20 mm; the metal monofilament is a copper monofilament;

[0027] The thickness range of the conductor shielding layer is 0.60~1.20mm; the thickness range of the insulation layer is 3.3~10.7mm; the thickness range of the insulation shielding layer is 0.60~1.50mm;

[0028] The first wrapping layer is formed by overlapping and wrapping a layer of copper tape.

[0029] In order to further improve the flame retardant performance of the cable, the third wrapping layer uses environmentally friendly glass fiber flame retardant tape. This type of material has the advantages of high strength, high temperature resistance, corrosion resistance, and flame retardancy. It can effectively isolate and prevent the spread of fire and improve the flame retardant performance of the cable.

[0030] Category 6 soft conductors are highly flexible and have good mechanical properties, and are not prone to breakage under long-term high-intensity torsion.

[0031] Preferred: The nominal cross-sectional area of ​​the conductor does not exceed 25mm 2 The copper monofilament is a bare copper monofilament with a diameter ranging from 0.12 mm to 0.20 mm.

[0032] Preferably: the outer sheath is formed by extrusion of an environmentally friendly thermoplastic polyurethane sheath material;

[0033] The conductor shielding layer and the insulating shielding layer are both formed by extrusion of environmentally friendly peroxide cross-linked semi-conductive shielding material;

[0034] The insulating layer is formed by extruding a cross-linked polyethylene environmentally friendly insulating material.

[0035] Preferably, the nominal thickness of the copper tape of the first wrapping layer is 0.15 mm, the nominal value of the overlap rate is not less than 15%, and the minimum overlap is not less than 5%.

[0036] This cable uses hydrogel material to form the anti-torsion layer, and achieves the two functions of anti-torsion and water-blocking / waterproofing with specific structural parameters. At the same time, this cable also uses polyurethane foam as filling, making full use of the water-blocking and anti-corrosion properties of the material, and improving the flame retardant performance of the cable.

[0037] After adopting new materials, this cable has a reasonable structure to ensure the electrical and mechanical properties of the cable.

[0038] After adopting the above technical solution, the cable has the following beneficial effects:

[0039] (1) The cable structure design is simple and reasonable: three cores are arranged in a triangle and twisted into a cable in accordance with national standards. The filling material is polyurethane foam, the production process is simple, and there is no need to park for a long time to release stress, which can greatly improve production efficiency. The polyurethane foam filling has almost no gaps, the cable has high roundness, high strength, strong waterproof performance, good flame retardant performance, environmental protection and non-toxicity, and good thermal stability.

[0040] (2) The conductor shielding layer, the insulating layer and the insulating shielding layer can form a three-layer co-extrusion structure. After dry chemical cross-linking, this structure greatly improves the low temperature resistance and physical and mechanical properties of the cable, and has a certain resistance to water treeing, so that the cable has higher mechanical safety and temperature resistance in the actual use environment.

[0041] (3) The flame retardant layer of extruded polyurethane not only meets the flame retardant performance, but also has a certain degree of waterproofness due to the characteristics of polyurethane. Polyurethane is an environmentally friendly material. After curing, it is non-toxic and odorless, and does not pollute the environment. The finished cable can be used in large-scale construction, rail transportation, medicine and other fields, and can withstand low temperatures of -45°C; the inner sheath can resist chemical corrosion and has good anti-aging performance.

[0042] (4) The extruded environment-friendly thermoplastic polyurethane outer sheath has good thermal insulation performance while meeting the traditional requirements for protection against external stress impact. Polyurethane can meet the requirements of no spontaneous combustion, no harmful gas release, and no collapse of the main structure under a flame temperature of 1200°C. Therefore, it can be used in places with high population density, such as shopping malls, office buildings, etc.

[0043] (5) Based on the introduction of new materials and new structures, the specific structure of this cable also ensures the requirements of the cable's electrical and mechanical properties.

[0044] This cable can pass the flame retardant B1 bundled combustion test in GB / T18380.33-2008, meet the qualified indicators of low toxicity performance in GB / T 19666-2019, and pass the water permeability test requirements in GB / T 12706-2020.

[0045] The utility model cable uses environmentally friendly filling and flame retardant layers and a specific structure to achieve the effects of improving flame retardancy, low toxicity and waterproof performance, and can be used in environments such as power generation, construction, rail transportation, and chemical industry that have high requirements for flame retardancy and environmental protection performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 Schematic diagram of the radial structure of this embodiment.

[0047] In the figure: conductor 1, conductor shielding layer 2, insulation layer 3, insulation shielding layer 4, first wrapping layer 5, filling 6, second wrapping layer 7, third wrapping layer 8, hydrogel anti-torsion layer 9, flame retardant layer 10, fourth wrapping layer 11, outer sheath 12. DETAILED DESCRIPTION

[0048] The present application is described below in conjunction with the accompanying drawings and specific implementation methods.

[0049] refer to Figure 1 , a low-toxicity, torsion-resistant medium-voltage power cable based on polymer hydrogel material, the structure of which is:

[0050] The cable core is wrapped with a second wrapping layer 7, a third wrapping layer 8, a hydrogel anti-torsion layer 9, a flame retardant layer 10, a fourth wrapping layer 11 and an outer sheath 12 in sequence from the inside to the outside.

[0051] The cable core is composed of three flexible wire cores and 6 fillers twisted together, and the cable pitch ratio ranges from 5 to 18 times;

[0052] In this example, filling 6 is flame retardant polyurethane foam filling. In the prior art, flame retardant polyurethane foam filling utilizes potassium ions to catalyze the rearrangement of carbamate groups and polyether segments of traditional soft polyurethane foam materials, so as to achieve rapid self-decomposition of soft polyurethane foam to produce a large amount of CO2 in a narrow temperature range before the soft polyurethane foam decomposes in large quantities, achieve self-extinguishing when away from the fire, and effectively reduce the concentration of toxic gases CO, HCN and NOx, so as to obtain excellent fire safety performance. In this example, the polyurethane foam filling can adopt the product of Shandong Tonglan Chemical Co., Ltd., model MDI.

[0053] The second wrapping layer 7 is composed of a layer of double-sided insulating water-blocking tape wrapped in an overlapping manner, with an overlap rate of not less than 45%;

[0054] The third wrapping layer 8 is composed of a layer of environmentally friendly glass fiber flame retardant tape wrapped in an overlapping manner, with an average overlap rate of not less than 25% and a minimum overlap rate of not less than 15%; in this example, the environmentally friendly glass fiber flame retardant tape can be selected from the WD-48 product of Ningjin County Hengjia Cable Accessories Co., Ltd.

[0055] The hydrogel anti-torsion layer 9 is formed by extruding an organic hydrogel, and the thickness of the hydrogel is 1.60-2.50 mm, and the thinnest thickness is not less than 1.2 mm; in this example, the hydrogel can be a product of Chongqing Haikuo Environmental Protection Technology Co., Ltd., model HK-5380. This product adds P(AM-AN-MA) / Fe3 to make the hydrogel have high-strength mechanical properties under high water content conditions, including low elastic modulus, high strength, high toughness and good self-recovery ability.

[0056] The flame retardant layer 10 is formed by extruding a polyurethane material, the nominal thickness of which is 2.50 mm to 3.50 mm, and the thickness at the thinnest point is not less than 85% of the nominal value; in this example, the polyurethane material is a polyurethane hetero-chain polymer material, specifically a product of Weifang Changxu Building Materials Co., Ltd., with a brand name of JSA.

[0057] The fourth wrapping layer 11 is composed of a layer of flame retardant heat insulating aramid tape wrapped in an overlapping manner, with an average overlap rate of not less than 30% and a minimum overlap rate of not less than 20%;

[0058] The outer sheath 12 is formed by extrusion of an environmentally friendly thermoplastic polyurethane sheath material, with a nominal thickness of not less than 2.50 mm and a thickness at the thinnest point of not less than 90% of the nominal value; in this example, the sheath material may be a product of Suzhou Ju'anhui Plastic Co., Ltd., with a brand / model of BT-1163D.

[0059] The structure of a single flexible core is: from inside to outside, conductor 1, conductor shielding layer 2, insulation layer 3, insulation shielding layer 4 and first wrapping layer 5;

[0060] The conductor is a Class VI soft conductor of a circular structure consisting of Class VI conductor bundles and multiple twists, and the diameter of the metal monofilament is not greater than 0.20 mm; the metal monofilament is a copper monofilament;

[0061] The first wrapping layer 5 is composed of an overlapping copper strip with a nominal thickness of 0.15 mm, the nominal value of the overlap rate is not less than 15%, and the minimum overlap is not less than 5%.

[0062] Category 6 soft conductors are composed of bare copper monofilaments bundled and twisted, with the diameter of bare copper monofilaments ranging from 0.12mm to 0.20mm; the diameter of category 6 soft conductors ranges from 2.1mm to 7.imm; the direction of the strand bundling and twisting of bare copper monofilaments is right-handed;

[0063] For cable cores with a pitch-diameter ratio of 5 to 12 times, the conductor has a nominal cross-sectional area not exceeding 16 mm 2 copper conductor; or for a cable core with a pitch diameter ratio of 13 to 18 times, the conductor is 25mm 2 of copper conductor.

[0064] The conductor shielding layer 2 and the insulating shielding layer 4 are both formed by extrusion of environmentally friendly peroxide cross-linked semi-conductive shielding material; the thickness of the conductor shielding layer 2 is in the range of 0.60 to 1.20 mm; the thickness of the insulating shielding layer 4 is in the range of 0.60 to 1.50 mm. In this example, the environmentally friendly peroxide cross-linked semi-conductive shielding material can be a product of Austrian Nordic Chemicals, with the brand LE0592 or LE0520.

[0065] The insulating layer 3 is formed by extruding a cross-linked polyethylene environmentally friendly insulating material, and the thickness of the insulating layer ranges from 3.3 to 10.7 mm. In this example, the cross-linked polyethylene environmentally friendly insulating material can be a product of Austrian Nordic Chemicals, with a brand name of LE4212.

[0066] In this example, the nominal thickness of the copper tape of the first wrapping layer is 0.15mm; the nominal thickness of the double-sided insulating water-blocking tape of the second wrapping layer is 0.35mm; the nominal thickness of the environmentally friendly glass fiber flame retardant tape of the third wrapping layer is 0.20mm; the nominal thickness of the flame retardant and heat-insulating aramid tape of the fourth wrapping layer is 0.30mm; and the nominal thickness of the outer sheath is 2.50mm to 6.00mm.

[0067] The structural performance advantages of polyurethane foam material used as filling material over traditional filling materials are as follows:

[0068] Polyurethane has excellent tensile strength, tear strength, impact resistance, abrasion resistance, weather resistance, hydrolysis resistance, oil resistance, etc. In the prior art, phosphorus-containing flame retardants can also be added to polyurethane foam materials to improve the flame retardancy of foam plastics, so as to delay combustion, block smoke, and even make the fire site self-extinguish. Polyols containing flame retardant elements (i.e., reactive flame retardants) can also be used as one of the foam raw materials.

[0069] This type of flame retardant can absorb heat and decompose into non-combustible substances at or near the ignition temperature, can react with the foam combustion products to generate non-combustible substances, and can decompose substances that can terminate the free radical oxidation reaction of the foam.

[0070] In polyurethane foam, phosphorus-containing flame retardants mainly play a role in the condensed phase. Phosphides can consume the combustible gases decomposed during the combustion of foam plastics and convert them into non-combustible carbonized products. When the phosphorus (P) content in the foam reaches about 1.5%, a better flame retardant effect can be obtained.

[0071] This example uses a polyurethane foam product of model MDI produced by Shandong Tonglan Chemical Co., Ltd., which is composed of a soft polyurethane foam material in which the carbamate group and the polyether segment are rearranged by potassium ions. A flame retardant soft foam material (FPUF) is prepared with aluminum diethyl phosphate (ADP) as an additive. Aluminum diethyl phosphate (ADP) improves the charring ability of the flame retardant soft foam material (FPUF), and can inhibit the overlap of oxygen and combustible gas between the flame and the polymer, thereby improving the flame retardancy of the flame retardant soft foam material (FPUF). Organic flame retardants have the characteristics of high flame retardant efficiency and little negative impact on the mechanical properties of the material.

[0072] The organic hydrogel anti-torsion layer of this cable utilizes the strong water absorption of hydrogel to make it have good water-blocking performance. Combined with the high-strength mechanical properties of a specific type of hydrogel product under high water content conditions, the anti-torsion performance of the cable is improved.

[0073] The test results of this cable are as follows, and the test results are qualified:

[0074]

[0075]

Claims

1. A low-toxic, torsion-resistant medium-voltage power cable based on polymer hydrogel material, characterized in that The structure is: It is composed of a second wrapping layer, a third wrapping layer, a hydrogel anti-torsion layer, a flame retardant layer, a fourth wrapping layer and an outer sheath wrapped around the cable core from the inside to the outside in sequence; The cable core is composed of a plurality of flexible wire cores and fillers twisted together, and the cable pitch-diameter ratio ranges from 5 to 18 times; the filler is flame-retardant polyurethane foam filler; The second wrapping layer is composed of a layer of double-sided insulating water-blocking tape wrapped in an overlapping manner, with an overlap rate of not less than 45%; The third wrapping layer is composed of a layer of environmentally friendly glass fiber flame retardant tape wrapped in an overlapping manner, with an average overlap rate of not less than 25% and a minimum overlap rate of not less than 15%; The hydrogel anti-torsion layer is formed by extruding an organic hydrogel, and the thickness of the hydrogel anti-torsion layer is 1.60 to 2.50 mm; The flame retardant layer is formed by extrusion of polyurethane material, the nominal thickness of the flame retardant layer is 2.50mm to 3.50mm, and the thickness at the thinnest point is not less than 85% of the nominal value; The fourth wrapping layer is composed of a layer of flame-retardant heat-insulating aramid tape wrapped in an overlapping manner, with an average overlap rate of not less than 30% and a minimum overlap rate of not less than 20%; The outer sheath is made of flame retardant sheath material extruded, with a nominal thickness of not less than 2.50 mm and a thickness at the thinnest point of not less than 90% of the nominal value; The structure of a single flexible wire core is: from the inside to the outside, it is the conductor, the conductor shielding layer, the insulation layer, the insulation shielding layer and the first wrapping layer; The conductor is a Class VI soft conductor with a circular structure, and the diameter of the metal monofilament constituting the conductor is not greater than 0.20 mm; the metal monofilament is a copper monofilament; The thickness range of the conductor shielding layer is 0.60~1.20mm; the thickness range of the insulation layer is 3.3~10.7mm; the thickness range of the insulation shielding layer is 0.60~1.50mm; The first wrapping layer is formed by overlapping and wrapping a layer of copper tape.

2. The low-toxicity, torsion-resistant medium-voltage power cable based on polymer hydrogel material according to claim 1 is characterized in that The nominal cross-sectional area of ​​the conductor does not exceed 25mm 2 .

3. The low-toxicity, torsion-resistant medium-voltage power cable based on polymer hydrogel material according to claim 1 is characterized in that The copper monofilament is a bare copper monofilament with a diameter ranging from 0.12 mm to 0.20 mm.

4. The low-toxicity, torsion-resistant medium-voltage power cable based on polymer hydrogel material according to claim 1 is characterized in that The outer sheath is formed by extrusion of an environmentally friendly thermoplastic polyurethane sheath material; The conductor shielding layer and the insulating shielding layer are both formed by extrusion of environmentally friendly peroxide cross-linked semi-conductive shielding material; The insulating layer is formed by extruding a cross-linked polyethylene environmentally friendly insulating material.

5. The low-toxicity, torsion-resistant medium-voltage power cable based on polymer hydrogel material according to claim 1 is characterized in that The nominal thickness of the copper tape of the first wrapping layer is 0.15 mm, the nominal value of the overlap rate is not less than 15%, and the minimum overlap is not less than 5%.

6. The low-toxicity, anti-torsion medium-voltage power cable based on polymer hydrogel material according to claim 1 is characterized in that The nominal thickness of the double-sided insulating water-blocking tape of the second wrapping layer is 0.35 mm; The nominal thickness of the environmentally friendly glass fiber flame retardant tape of the third wrapping layer is 0.20mm; The nominal thickness of the flame-retardant and heat-insulating aramid tape of the fourth wrapping layer is 0.30 mm; The nominal thickness of the outer sheath is 2.50mm to 6.00mm.

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